Today after I installed Ubuntu 16.04 via USB on my pre-installed Windows 8 machine, I was required to restart my computer. After doing so I wasn't offered to select an OS, so after searching the internet, I came across Boot-Repair which I ran using the Try Ubuntu option in my Ubuntu installation USB.

Following the boot repair I got a message saying,

If your computer directly reboots into Windows, try to change the boot order in your BIOS. If your BIOS does not allow to change the boot order, change the default boot entry of your Windows bootloader. For example, you can boot into Windows then type the following in an admin command prompt:

bcdedit /set {bootmgr} path EFIubuntushimx64.efi

After I rebooted my PC, I am receiving the following error message for about 3 seconds, after which it boots automatically into Windows 8, without letting me access Ubuntu.

Error received while booting after manufacturer's logo, before grub:

Failed to open EFIBOOTgrubx64.efi - Not Found  

Failed to load image EFIBOOTgrubx64.efi: Not Found    

start_image() returned Not Found  

So I tried the other solution of typing that command in the cmd, to which my surprise, worked, and I am now prompted a window (grub) to choose my OS each time I turn on my PC, but unfortunately, I still receive an error each time, that lasts about 3s, after which I can choose my OS (both are working just fine) and work normally.

Do you have any suggestions to get rid of the error message each time I boot my PC?